Studies On Tree Leaves, Bark And Rings As Bionidicators Of PBDEs And Heavy Metals In Air

E-waste contained toxic and harmful substances such as polybrominated diphenyl ethers(PBDEs)and heavy metals,which could be released into the environment through a variety of ways in the recycling and disposal of waste electrical and electronic equipment,caused damage to the environmental pollution and human health.This study on the typical e-waste recycling site and surrounding area(Wenqiao Zhen,Yanggongao,Mukeng and Changyudongtian)in Wenling City,Zhejiang Province.The concentrations of PBDEs and heavy metals(Cr,Mn,As,Co,Ni,V,Sn,Pb,Se,Sb and Se)were detected,the concentrations of PBDES and heavy metals in different environmental media were compared,and pollution levels and distributions characteristics were analyzed.The sources of PBDEs homologues and heavy metals were investigated and the risk assessments were conducted.Discussed tree leaves as bionidicators of PBDEs and heavy metals pollution in the atmosphere,analyzed the concentrations of PBDEs and heavy metals in leaves influenced by tree species,lipid content,leaves ages,sampling heights,and so on.Discussed tree bark as a bionidicator of PBDEs pollution in the atmosphere,analyzed the concentrations of PBDEs in tree bark influenced by tree species,lipid content,tree ages,sampling depths and heights,and so on.Discussed tree rings as bionidicators of PBDEs and heavy metals pollution in the atmosphere,analyzed the concentrations of PBDEs and heavy metals in tree rings influenced by tree species,sampling heights,longitudinal samples,radial samples,and so on.The innovation of this research was applied to tree bark,leaves and rings as bionidicator to PBDEs and heavy metals in air at e-waste sites,the PBDEs concentration distributions and pollution status in different polluted sites were evaluated to provide scientific basis for the prevention and control of PBDEs pollution.The results as follows:(1)PBDEs were prevalent in all environmental media in four sites,and the thend of concentration changes was the same as recycling regions>controlling regions.PBDEs homologues were mainly composed of BDE-209 in WQZ,YGQ and MK.Heavy metals were prevalent in all environmental media in four sites,and the thend of concentration changes was the same as recycling regions>controlling regions.There was a positive correlation between PBDEs in the environment media.Sn,Pb,Cu,Cd,As and Ni in air,dust and soil were significantly correlated each other,the results showed that Sn,Pb,Cu,Cd,As,Ni and other heavy metals in the environment might come from the similar sources of pollution.(2)The trends of PBDEs concentrations in tree bark and in the atmosphere both were:MK>YGA>WQZ>CYDT.Tree bark could indicate PBDEs pollution well in the atmosphere as a bionidicator.There was a positively relationship between PBDEs concentrations in tree bark and PBDEs concentrations in the atmosphere,indicating that PBDEs in tree bark mainly derived from the atmosphere.Tree bark could enrich PBDEs in the atmosphere and could be used as bionidicators of PBDEs pollution in the atmosphere.The concentrations of PBDEs in tree bark were affected by tree species,lipid content,bark sampling depth,tree ages,and so on.(3)When tree bark was used as a bionidicator of PBDEs pollution in the atmosphere,tree species should be selected with large specific surface area,20 to 40 years old,tree bark depths of 0 to 2 mm(such as Salix babylonica,Cinnamonum camphora and Pinus massoniana)to minimize the uncertainty of PBDEs concentrations due to differences in sampling methods.(4)The trends of PBDEs and heavy metals concentrations in leaves and in the atmosphere both were:recycling regions>controlling regions,that was MK>YGA>WQZ>CYDT.There was positively relationship between the concentrations of PBDEs and heavy metals in leaves and the concentrations of PBDEs and heavy metals in the atmosphere,indicating that PBDEs and heavy metals in leaves mainly derived from the atmosphere.Leaves could be used as bionidicators of PBDEs and heavy metals pollution in the atmosphere.(5)The concentrations of PBDEs and heavy metals in leaves were affected by tree species,lipid content,leaves ages,and so on.When leaves were used as bionidicators of PBDEs and heavy metals pollution in the atmosphere,it is suggested that leaves of evergreen trees are recommended,and considered the effects of the above factors on the concentrations of PBDEs and heavy metals.(6)There was positively relationship between the concentrations of PBDEs and heavy metals in tree rings and the concentrations of PBDEs and heavy metals in the atmosphere,indicating that PBDEs and heavy metals in tree rings mainly derived from air.Tree rings could indicate PBDEs and heavy metals pollution well in the atmosphere and could reflect the age variations of PBDEs and heavy metals pollution in the atmosphere.The concentrations of PBDEs and heavy metals in tree rings were affected by tree species,sampling height,radial depth and others factors.(7)When tree rings were used as bionidicators of PBDEs and heavy metals pollution in the atmosphere,it is suggested that tree species such as Magnolia grandiflora,Cedrus deodara and Metasequoia glyptostroboides should be selected,and the DBH of trees heights should be as the best sampling heights,and radial samples should be chosen from trees more than 30 years old to minimize the uncertainty of PBDEs and heavy metals concentrations due to differences in sampling methods.